MHST Guy

This one is completely different from the other topic though. The truck is an '86 4Runner with 244k miles. 100% stock, recently replaced fuel filter, plugs, wires, cap, rotor, injector flush, top end cleaner, air filter, O2 sensor, inspected all vacuum lines, adjusted the rocker arms, and a few other things I'm probably forgetting. This problem doesn't happen all the time, which makes it even more confusing. It can happen on start up, or after its driven a few miles, hot or cold, etc. When it happens, it makes a loud popping noise, and acts like it's running on 2 or less cylinders.

Now this truck has always been slow. Highways are not an option, and you have to floor it just to keep up with regular traffic. I recently discovered that the timing chain was 1 tooth off on the cam gear, so I figured that was the problem. I fixed this problem, but when I went to time the distributor, I noticed that by shorting what I think is the T-terminal the timing mark didn't move (I was shorting the two pronged connector that normally is disconnected on the driver's fender well. Is this right?). I tried setting it at 5*, and it felt a little better, but the problem still existed.

On all of the other vehicles I've had to time, when you disconnect whatever is required the timing mark moves. Since I saw no movement, I'm assuming that the car is running as it normally would at idle, with a decent amount of timing. So I reset my timing by ear, ending up with the distributor bolt close to being in the middle of the adjustment slot, like I'm assuming it should be close to. The truck picked up a bunch of power (highways/speeding tickets are now a possibility) so I thought I fixed the problem. Apparently not. It still pops, sputters, and frequently dies and is nearly impossible to get restarted. I'm at a complete loss. Any thoughts? I really appreciate your time

toy_tek

Sounds like a fuel delivery problem. Have you checked the fuel pressure at the manifold rail? Are you getting a check engine light?

Also I think the shorting connector is mounted to the engine on the drivers side, IIRC. All you do is pop the cap, not disconnect a plug. And I don't recall seeing anything move when shorting it, but its been a few years since I had my 87. Is your timing set by the sticker on the hood? Spark plugs gapped properly?

MHST Guy

I haven't checked fuel pressure, and the CEL only comes on when it is close to dying (~300 RPMS)

The plug I'm using isn't connected to anything, and there is no cap on it. I'm just shorting the two terminals with a paper clip, and setting timing to what the sticker says underhood.

toy_tek

Ok, sounds like the right plug.

I'm not sure what that fuel pressure is supposed to be but it would be worth checking to see if it is falling or fluctuating prior to the problems your having. I'm sure the FSM will give the required range. Also could you have water in your tank? Does the problem get better or worse when your fuel tank is full or empty? How about ambient temperature... any effect?

Does the CEL light stay illuminated after it dies and you start it up again? I'm guessing it doesn't.

MHST Guy

Ambient air temp has nothing to do with it (although it has been butt-ass cold in Denver recently). Currently the tanks is almost on empty, so I guess that could be the problem..

FSM = factory service manual?

toy_tek

Yes: Factory Service Manual.

If you keep your tank low on fuel frequently, condensation can build up inside and the water sits at the bottom where the fuel pickup is.

Not saying that is your problem, just considering some possibilities.

MHST Guy

I have the 85 FSM so it has the 22RE motor, I just have to sort through the 22R motor stuff as well (so if anyone has the 86 FSM in .pdf format, please let me know!). I'm really starting to think you might be correct about the water in the tank thing. I'm about to go try to drive it to the gas station and see if a fill up fixes (temporarily) the problem. Thanks for your help

MHST Guy

Ok, the fill up did nothing. This truck is my wife's DD, so when I asked her if it was throwing an engine light she said no, but when I just drove it the light turned on when it was misfiring. The codes I pulled were 3, 6, 7, 10, 11, and 12 which mean ignition signal, RPM signal, TPS signal, started signal, switch signal (anyone know what switch this is talking about?), and knock sensor signal, respectively.

I disconnected the battery to reset the computer (hoping like an idiot that this would fix the problem). After ten minutes I hooked it back up and let it idle for a bit. It idled perfectly for a few minutes, then it started to misfire. The misfire slowly got worse, but it would go away if I revved the motor. I went for a test drive, and the misfire issue is still present. Now the codes it's pulling are 3, 6, 7, 10, and 11 (no 12 this time). Any thoughts? I'm starting to think it could be a bad ignition coil, fuel pump, ignition switch, or even the ECU itself

toy_tek

Did it start this problem after changing all those parts, or was it doing it before?

After it misfires and shuts down, pull all your spark plugs and see which cylinders are misfiring. The plugs should be dry and brownish white. If any are wet and/or burned or black those are your misfiring cylinders. Then swap those plug wires with the wires on the good cylinders. Run it again until it misfires, remove the plugs, and see if the problem follows the wires or stays with the cylinder. This way you can eliminate (or diagnose) the wires as a possible cause. Inspect all the terminals on the cap, as well as your rotor if you haven't already.

FSM will have troubleshooting for each code you pulled. My guess is you have one problem that is triggering the rest.

MHST Guy

It started once I adjusted the cam timing. I'm thinking that whoever installed this motor (or at least had the timing chain off) accidentally installed the gear one tooth off. He/she then proceeded to try and tune out the issue, making it run slightly better at the time but overall worse than any stock truck should run.

I just remembered that there has always been a hissing noise coming from the air meter (the thing at the end of the intake crossover tube). I've had that tube off several times looking for a crack, but never found anything. I've tried spraying brake clean all around with the engine running to see if the RPM's increase (aka spraying into a leak) but never found any. So I'm going to try to adjust the IAC screw, and then readjust the idle screw and hopefully tune out the hissing from the air meter.

Also the brake pedal feels like $#it. It's really spongy, so I'm thinking that I have a bad power booster as well. I'm not thinking that this is a related problem, but does anyone on here see a correlation?

Thanks for your time with this issue

MHST Guy

Ok, it's better now that I've adjusted the idle and the air bleed screw, but it still sputters occasionally. Any other thoughts?

MHST Guy

Anyone? I checked the fuel pressure, and it was around 32 PSI, and increased when I revved the motor. It still sputters at idle, and surges when accelerating. All of the spark plugs look the same, and I've pulled each plug individually and then ran it, but it still sputters no matter which one is removed

Issues

Are the spark plugs bottoming out with the head? Just asking cause i had a friend who bought a 88 yota. And it had a miss upon acceleration & also while idling. He had me adjust the valves & time it & it was still there. What i found is that the last person you had it had screwed up the plug threads at #4 cylinder. So when you installed the plug and tightened it, that when it did so the electrode part of the plug was still located in the threaded part. So that cyinder was even lucky if it got fire. I ran a thread chaser through it (carefully) and after making sure there was no shavings in cylinder, we installed the plug. It went in all the way and made contact with the head this time. It no longer has a miss and it runs stronger. Worth checking!

MHST Guy

Thanks, but I've had these plugs in and out 4 times now, and they all go in the same amount. Anyone have any thoughts?

BTW, the truck held fuel pressure after it was shut off, so it isn't an injector stuck open.

MHST Guy

I replaced the plug wires, and now it isn't stumbling when driving. But it still misfires when at idle. I guess I'll just replace the plugs and cap/rotor and see what it does.